The Bristol Mercury IX was a British radial engine used as the power plant for the Gloster Gladiator Mk I, the Fokker D.XXI, and the Bristol Blenheim. Developed from the Bristol Jupiter, it was conceived and produced to power small and medium size aircraft, such as fighters and small bombers. The Bristol Jupiter had been designed at the end of World War I to power British biplanes of the interwar period. The other widely-used versions developed from this radial engine were the Bristol Mercury VI-S and the VIIIA, which constituted the power plants for the Gloster Gauntlet and the Gladiator Mk II variant respectively.
Technical Characteristics
The Bristol Mercury IX was a 9-cylinder, air-cooled, radial, piston engine, with superchargers. It could deliver between 830 and 845 horsepower. There were two openings in front of each cylinder, working as exhaust ports. These were connected to the collector rings on the cowling. Two spark plugs were fitted atop of each of the nine cylinders. The Mercury had a black crankcase with aluminum cylinders. The nine cylinders drove the airscrew shaft, which turned either a two or a three-blade propeller. It employed 100-octane aviation gasoline.
Specifications
Type: internal-combustion, radial, piston engine.
Weight: 450 kg (980-lb)
Length: 1.2 m (47 inches)
Diameter: 1.3 m (51.5 inches)
Stroke: 16.5 cm (6.5 inches)
Compression Ratio: 6:1
Carburetor: Claudel-Hobson
Supercharger: single-speed, centrifugal type.
Below, a 1930s picture of a Bristol Mercury IX radial engine before it was mounted in the nose nacelle of the Gloster Gladiator biplane fighter.
